The nation’s pilots, truckers and train engineers are in need of some shut-eye. And not just one of those gulps of instant energy.

According to a major new study from the National Sleep Foundation, these transportation operators are sleepier than average American employees, and the lack of rest puts them at greater risk for accidents.

About 26 percent of train operators and 23 percent of pilots say sleepiness affects their job performance at least once a week, compared to 17 percent of workers in nontransportation jobs. One in five pilots, along with 18 percent of train operators and 14 percent of big-rig drivers, report that they’ve made “a serious error” or had a “near miss” as a result of being tired, the study shows.

About 6 percent of pilots and train operators say a lack of sleep has directly led to a car accident during their commutes to or from work, compared to just 1 percent of workers outside the transportation business.

Nearly 60 percent of train operators, half of all pilots and 44 percent of truck drivers say they rarely or never get a good night’s sleep on a work night, according to the survey. Meanwhile, the same complaint came from just 29 percent of bus drivers, taxi drivers and limousine operators, who report that their schedules allow more regular and sleep-friendly hours than those other transportation workers.

“The margin of error in these professions is extremely small. Transportation professionals need to manage sleep to perform at their best,” said David Cloud, CEO of the National Sleep Foundation. “As individuals and employers, we need to know more about how sleep improves performance.”

The sleepiness of America’s pilots and truck drivers has gotten plenty of attention from federal officials in recent months, and the Obama administration recently crafted new rules to govern the work schedules of employees in both sectors.

In late December, the administration released new guidelines for pilots, requiring that they take at least 10 hours off between shifts, a two-hour increase over previous standards.

That same month, federal officials unveiled new “hours of service” rules for tractor-trailer drivers, which cut the maximum work week from 82 hours to 70 hours. The measure also instituted a 34-hour “restart period” each week, meant to ensure drivers get two days off for every five days on the job.

But the restart provision prohibits drivers from getting back behind the wheel before 5 a.m., and industry leaders believe that the mandated start time will do little to improve roadway safety and will instead lead to heavier traffic congestion during morning rush hour.

Last month, the American Trucking Association filed suit in D.C. Circuit Court asking a judge to review the new regulations, which were written by the Federal Motor Carrier Safety Administration, an arm of the Transportation Department.

“This is an issue that’s not going to be settled anytime soon,” ATA spokesman Sean McNally said. “It’s important to say that not everything in [the sleep foundation report] is necessarily good for the trucking industry. There are clearly areas that we need to make improvement on. But the drivers we talk to tell us that they know their bodies, they know when they’re tired.”

While truck drivers and other transportation workers may get less sleep between shifts, they often enjoy something most employees can only dream of: naps during the work day.

Nearly 60 percent of pilots and 56 percent of train operators report taking at least one nap during the day, compared to 27 percent of workers outside the industry. One out of every five truck drivers reports taking three to five naps during the work week, the study shows.

Of those snoozing workers, half of all pilots, 42 percent of truck drivers and 33 percent of train operators reported recently taking a nap while on the clock. Only 19 percent of nontransportation workers say they nap during their shifts.

“Transportation workers have challenging schedules that compete with the natural need for sleep,” said Thomas Balkin, a sleep researcher at the Walter Reed Army Institute of Research. “While I’m impressed that transportation professionals nap when they are off duty, we need to better understand how to use naps to reduce sleep deprivation and overcome schedule issues.”

The survey, the first to ask transportation employees about their sleep habits, was based on interviews with 1,087 working adults, including 202 pilots, 203 truck drivers, 180 rail workers, 210 bus, limousine or taxi drivers, and 292 people working outside the transportation sector.